Chilly!

Florida family: 36F/2C !! (Brother sent a photo of nephew wearing a “hoodie” sweatshirt to stay warm while eating breakfast– however, green grass and lush shrubbery can be spied through the window.)

This might be as good a day as any to discuss the perennially-asked question, “How do you keep your pipes from freezing?” (Also sometimes phrased in the form of a statement, such as, “You dumb #&#*. You’ll be #&*(ing sorry when your #%%#ing pipes #*(%@#ing freeze ha ha haaa!”) Anyway, it’s a good and valid question. In the old days, people had wells and outhouses; the limiting factor for how cold a house could be kept was the bodily tolerance of the human inhabitants. Nowadays, with fancy indoor plumbing, the limiting factor is the point at which pipes start freezing.

Those who live in tropical climes may not fully appreciate the hazards of frozen pipes. The best case scenario is that the water freezes in a pipe, temporarily clogging it, then when thawed, the water goes on its way without having caused any damage. However, because water expands when it freezes, there is a tendency for pipes to crack when the water in them freezes. In the worst-case pipe-burst scenario, the water in the cracked pipe is under pressure (i.e., it’s a water supply line, rather than a drain pipe), and you are away on vacation in Tahiti when it all happens. Then you may have thousands of gallons of water sprayed into your home. You could, for example, come home to a scene like this (only it might be in your living room, instead of your garage)(good thing these folks have AAA!)

Obviously, this is bad. How to avoid? For cold-house living, I propose four phases of action to avoid frozen pipes: (1) Assessment, (2) General prevention, (3) Monitoring, (4) Acute Prevention. Let’s review each!

Assessment: First, you need to know where all your water pipes are. In particular, you need to know if any of them run through the outside walls of your house. In my opinion, it’s crazy to run pipes through outside walls anyplace where winter temps routinely go below freezing, but strangely it is done, even up here. If you have such plumbing, you should probably forget going cold-house until you’ve addressed it somehow. Case Report: My good friends S. & J, for example, discovered this winter that the previous owner of their house had created some outside-wall pipes, by “finishing off” an area of the cellar with drywall. Some of their pipes, previously open to the cellar, were thus sealed off against an outside brick wall. Worse yet, they found the previous owner had put in some insulation– not between the pipes and the outside wall, but between the inside wall and the pipes! Effectively, these pipes were outdoors. Evidently those people used the cellar area for a dog-grooming business, and so kept it very warm, and this was enough to prevent disaster. But J. & S. did what normal people might do– kept the cellar temp in the 50’s– and then one very cold morning last month found they had no water pressure in any of their taps. Diagnosis involved cutting many holes in their walls, and cure involved warming the pipes. Here is a photo:

Thanks to unbelievable luck, none of their pipes had burst. The mess would’ve been ungodly.

Here at the Cold House, we don’t have any pipes in outside walls. We do have one half-bath in a detached part of the house that we don’t even try to keep warm in winter– that area is basically ambient outside temp now. Beyond that we do have pipes in a few dubious areas of the main house– for example, running through a closet that has a door to the living room but is otherwise adjacent to an outside wall and the closed-off guest room. Also there’s a spot in the cellar where some pressure water lines and a bathtub drain pipe run about 4″ away from a crummy old window and our cat-door (which is a little drafty). So those were areas of concern. Early in the winter I took the remote sensor from the digital thermometer around to these areas and checked them out. I decided that that area in the cellar was going to be the coldest pipe-location in the house.

General Prevention: The next step is doing something about the potential problem areas. One solution, as employed by the previous owners of J. & S.’s house, is simply to overheat every part of the house, whether in use or not. There are also various commercial products, such as this stuff, that apply electrical heat to your pipes to keep them above freezing. This isn’t a bad idea, but is kind of a pricey hassle. Insulation may be easier and cheaper. Of course, pipes don’t really have any innate heat, so just wrapping them in a blanket won’t keep them warm– but insulating cold areas nearby can prevent them from getting cold. In our case, I stuck some fiberglass mat insulation over the cellar wall and window near the pipe area; this made a considerable difference. (As for the half-bath in the detached area: before winter I shut off that water supply, drained the related water pipes completely, and ran non-toxic RV antifreeze down the drains & toilet. Having winterized boats helps with that skill-set, but it wasn’t hard.)

Monitoring: Having checked out the pipe situation and done a few things to ameliorate anticipated problems, you can start to get a sense of whether you’re going to have actual problems. As the days grow colder, I began to get a sense of how fast the house cooled, and where, and how much this was effected by different sorts of weather. This is information I simply didn’t have when a furnace automatically kept the house at 68 (days) or 62 (nights) all winter long. But after watching the thermometer for a while, and moving its spare sensor from place to place in the house, I began to have a feel for what was going to happen. Eventually I put the wireless sensor right on that pipe in the cellar. The first really cold night (the night where my friends’ pipes froze) I brought the thermometer station up to bed with me, and woke up a few times, panicked, to check the pipe temperature. It didn’t get below 40, in spite of the sub-zero temps outside. Since then, I monitor it a bit if the forecast predicts an especially cold night.

Acute Prevention: If things are looking bad for the pipes on a given night, the simplest thing to do is just leave the water running at a trickle. Basically geothermal heating of your pipes– the incoming water from below ground being somewhere above freezing. You could even leave the hot water tap open a bit, but that’s probably overkill. The tub drain mentioned above has a large trap below it, holding a cup or two of water– I’d consider pouring a little of the RV antifreeze in there, if it was going to be -20F overnight, but so far it’s been unnecessary to go to such extremes.

Nope, haven’t made any measurements, because haven’t yet employed this strategy. But I’d guess that a gallon per threatened tap per night would be more than enough to ensure safety in most cases. That’s probably the equivalent of one toilet flush per night, at most.

We’ve had very cold nights where we’ve had to leave water running. So not to waste the water (especially since we pay for it) I put buckets under all faucets. Then use the water to water plants and for dishes. Or we put it in the tiolet tank. But that has only happened twice in seven years. I grew up in Northern Maine where the temp. with wind chill would get to be -50.

When I was a child living with my family in central New Jersey, I remember very cold winters when the pipes that ran from the well to the house froze. It was just a short distance – maybe 10 feet. I can still picture my dad digging down to the pipes through the frozen ground to get at the pipes. I have no idea what he did once he exposed the pipes, but I know he was always able to get the water flowing again…this happened several times over the course of the 6 years we lived there. I vividly remember that he was not a bit happy about the task!

I have not used my furnace for 3 years. I use electric space heaters in the occupied rooms of my home (I am very careful about placemenent of these) and I bundle up indoors every night. I do have pipes on outside walls (what were the builders thinking?) and have had burst pipes on two occassions, once even when I left the pipes trickling. I am fourtunate to have my main water shut-off inside my house and I have since solved the pipe problem this way: Last thing before bed I turn the water off at the main and then open all faucets to drain the pipes, including flushing the toilet. I also shut down the water heater so it is not trying to heat a half filled tank. As soon as I get up in the morning I turn the water on, letting all faucets run for a minute or so to bleed the air out, and then I close them and turn the water heater back on. I have hot water in 40 minutes and never have to lose sleep worrying about the pipes. When the temps stay below freezing during the daytime I will repeat this process before I leave for work so the pipes are safe while I’m gone all day. This process works like a charm.

Darc, you are HARD CORE! I knew that being on the news would flush out people who have been doing this longer, better, and more intensively that us. It’s inspiring! I’m curious about your water regimen though– assuming your water shut-off is in the cellar or ground floor, how does opening faucets at higher levels drain the system? Seems to me you’d have to drain it at the low point. Can you explain?

I put our water heater on a timer (specifically designed for the purpose)– it’s off all night, automatically (and extremely insulated, though– though since it’s the only source of heat in the cellar, I sometimes wonder if I should insulate it a bit less!)

CHJ,
My house is one story and built on a slab. My pipes are in the attic, so this accounts for the success of draining them. Actually, I never thought about that before…would this work if the pipes are the basement? I’d like to hear if someone tries it because I had intended to use this process when I move.

Still, I think the air pressure flowing into the pipes might create enough pressure to drain them. I know that my pipes don’t really start flowing until I’ve opened all of them.

Love the water heater timer idea…I’ll look into that just for general cost savings.

Don’t send your lawyer but by opening up piping to atmospheric , you’re measurably eliminating the possibility that expanding water (aka ice) within can pressurize the system to catastrophic: any increasing pressure would first have to compress the air occupying the pipe. If the water/air ratio is minimal, there’s room (and a direction: pressure -> no pressure) for more expansion; with open faucets pressurization should never occur: the pressure will push ice dams to them. The classic experiment of course is putting two equivalent bottles of water in your freezer overnight, one capped tight and the other uncapped. I’d bet the ranch that in the morning you will find that the capped one will have fractured and the other will not have . In plumbing systems, you may have to account for awkward bends and turns so getting as much water out and at the lowest point is optimum; leaving faucets open though is necessary…”High pressure goes to low.” is a phrase steam heat aficionados know well; only 1/2 a pound of pressure is needed to move enough steam to heat a home (when we do want heat). It may behoove all to learn how to sweat a joint and, as a SUMMER project (unless you’re REALLY HARDCORE) install a shutoff valve with a drain as close to the water source as possible.

Hi! I have a question for “Darc” – on the posting from today (Jan 23).

I’ve lived in California most of my life & have since relocated. Lots of snow & cold! This whole freezing pipe thing is a brand new concept for me!

My question: is it not still possible for your pipes to freeze, even though you’ve shut the water off? I’m guessing they could still freeze, but you wouldn’t have the mess because you’d discover the problem right away when turning the water back on?

In fact the water did freeze in the pipes once last year. In that case it was only one faucet that wasn’t geting water (the bathtub because the pipes run down the outside wall). I had to wait an hour or so that morning for the ice dam to thaw in that pipe and then the water flowed fine, and no burst pipe.

So, you are right. It is still possible, maybe even likely, for the small amount of water left in the pipes to freeze but, in my experience, there is no damage caused by it. I’m sure there would be variations depending on the configuration of the plumbing, etc. I can only relate my own experience and hope that it works as well for someone else.

I’ll chime in with my two cents on this question. I don’t think that shutting off the supply valve and opening a faucet at the other end can possibly reduce the chance a pipe will freeze (assuming it’s still full of water.) Just relieving water pressure in the pipe will not affect the freezing point of the water in any appreciable way*.

However, I can see two benefits to taking these actions. A theoretical one is that if/when the pipe does freeze, it may be a bit less likely to burst. The burst occurs because the water expands on freezing, but is constrained within the pipe. If you have a faucet open at the other end, that might allow the forming ice to expand lengthwise through the pipe, which in turn might let it expand a bit less in a horizontal direction. But I think unless the pipe is very short, the likelihood of this helping is minimal.

More importantly, though, if the pipe bursts and the water in it isn’t pressurized, at least when it thaws it won’t spew thousands of gallons of water into the house– it will just drain the few gallons contained in pipe.

* [Of impractical interest: pressurizing water actually lowers its freezing point slightly, so in theory keeping the supply valve open would let the pipes get colder before they freeze. But as you can read here, the effect is trivial. In order to lower the freezing point by 4ºF, you’d need about 3,600 psi of pressure– which is probably almost 100 times normal house-water pressure, and probably enough to blow your whole plumbing system apart!]